1. Technical Field of the Invention
This invention relates to a method for the purification of a polyoxyalkylene feedstock selected from the group consisting of polyoxyethylene glycols, polyoxypropylene glycols and C.sub.1 -C.sub.4 monoalkyl ethers thereof having molecular weights of about 200 to about 5,000 and contaminated with more than about 100 parts per million of alkali metal or alkaline earth metal ions. In accordance with the present invention, the feedstock of the present invention is mixed with about 2 to about 10 wt. % of water, based on the weight of the feedstock and, if the feedstock is a polyoxypropylene glycol or a C.sub.1 -C.sub.4 monoalkyl ether thereof, it is additionally mixed with from about 30 to about 70 wt. % of a polar organic solvent. The resultant charge stock, comprising a feedstock contaminated with more than about 100 parts per million of alkali metal or alkaline earth metal ions is brought into contact with a basic ion exchange resin (Amberlite.RTM. IRA-743, a styrene-divinyl benzene ion exchange resin in the free base form) under treating conditions including a temperature of about 25.degree. to about 100.degree. C. and a pressure of 0 to about 100 psig. for a period of time sufficient to lower the impurity level of the ions in the feedstock by at least about 90% to an impurity level of less than about 100 parts per million.
The basic ion exchange resin to be used in accordance with the present invention is a fully hydrated boron specific basic styrene-divinyl benzene ion exchange resin in the free base form having an apparent density of about 40 to 45 lbs. per cubic foot.
2. Prior Art
Amberlite.RTM. IRA-743 is a boron specific ion exchange resin manufactured by the Rohm and Haas Company of Philadelphia, Pa. The precise composition of the ion exchange resin is the proprietary information of the Rohm and Haas Company who, in their brochures, describe the ion exchange resin as a boron-specific ion exchange resin in the free base form, that applicant understands to be a styrene-divinyl benzene ion exchange resin, that is sold as fully hydrated spherical particles having a moisture content of about 58% and an apparent density of about 40 to 45 lbs. per cubic foot (640-720 g/l). Rohm and Haas state that Amberlite.RTM. IRA-743 is a unique ion exchange resin that is specific for borate and boric acid under a variety of conditions. This is the only stated use for the product.
The use of Amberlite.RTM. IRA-743 is described in an article entitled: "Boron Removal from Industrial Effluent by Ion Exchange" by Buzzard et al. (Toxic Hazard Wastes, 1987, 218-226).
Another use of the resin for the removal of boric acid and related compounds from solutions of carbohydrates is described by Hicks et al. (Carbohydr. Res, 1986, 147(1), pages 39-48).
Yet another use of Amberlite.RTM. IRA-743 in the treatment of wastewater containing fluoroborates is disclosed by Iwaya, Yoshiaki et al. in JPN. KOKAI TOKKYO JP 60,172,39 [85,172,392] (Cl. C02f/42) 05 Sept. 1983, Appl. 84/29,235, 17 Feb. 1984.
Still another use of the resin for the recovery of boron from natural gas brines is disclosed by Yasuda, Sejii et al. (Gov. Ind. Res. Inst., Tosu, Japan 841 Nippon-Kagaku Kaishi 1987, (4), 752-6 (Japan).
Amberlite.RTM. IRA-743 has also been used to remove arsenic from wastewater Unitaka Ltd. Jpn. Kokai Tokkyo Kobe JP 58 64,180 [83 64,180] (Cl. C02F1/42). 16 Apr. 1983, Appl. 81/163,819.